A home air conditioning unit is well known and many embodiments are available. A typical air conditioning unit contains a heat exchanger or condenser and evaporator. Both of these units include a coil. The coil in the evaporator contains a coolant, such as a freon gas, which has been compressed to lower its temperature. Air from inside the home is passed over the coil and is cooled by the coolant positioned within the coil. The coolant is recycled through the condenser wherein it is recooled through compression. The heat picked up by the coolant when passing through the heat exchanger is then transferred to the ambient air passing over the condensing coils. The present invention is not concerned with the air that is used to cool a house, but rather, the present invention is concerned with the air which is used to cool the operating machinery such as the condenser. A condenser unit exchanges the heat from the coolant to the ambient air passing over the condenser coils. Accordingly, more heat can be transferred by the condenser when the temperature of the ambient air is low. Typically, the temperature of the ambient air varies from climate to climate. The compressor works harder when the ambient air temperature is above that selected as the design temperature at which the condenser is rated. The rating is normally given in tons or BTU'S of a cooling power. Most air conditioners are reated at an ambient of 95.degree. F.
The condenser works more efficiently below the design temperature than above. Typically, in those climates having ambient air temperatures above 95.degree. F, the efficiency of the condenser is reduced in its job of lowering the temperature of the coolant. In this environment, the compressor works longer to provide the required cooling to the coolant. The longer the compressor operates to cool the coolant, the more energy is required to operate the compressor and the more wear and tear the compressor experiences. The additional energy means an added expense to pay for the power. The more wear and tear the compressor experiences, the oftener it must be serviced and/or replaced at more additional expense.
Another term used in identifying the operating condition of a compressor is that of "coolant differential temperature." The "coolant differential temperature" is the difference between the temperature of the desired inside air identified by the thermostat and the temperature of the coolant. Under optimum operating conditions, the "coolant differential temperature" should be within the range of 19.degree. to 21.degree. F. However, through a loss of efficiency, the prior art systems are not able to provide this "coolant differential temperature" and the volume of air to be cooled, i.e., a house, is cooled by a coolant having less than the best "coolant differential temperature," i.e., 14.degree. or 15.degree. F. Under these circumstances a greater "on time" is required to reach the temperature identified by the thermostat.
A special form of the problem of not reaching the required "coolant diferential temperature" occurs when a structure is built with an air conditioning unit which just barely provides the required amount of cooling power at the rated temperature. When the ambient temperature exceeds the rated temperature, the air conditioning unit is not able to deliver coolant with the proper "coolant differential temperature" sufficient to reach that cooling level identified by the thermostat. In this situation the air conditioner runs continuously with a waste of power.
One term used in identifying the operating condition of a compressor is head pressure. The term head pressure indicates how hard the compressor is working in order to compress the coolant material used in the air conditioning system. Just as the air conditioner has an ambient design temperature, i.e., 95.degree. F, at which the air conditioner is rated, the condenser unit has a head pressure rating to indicate its maximum allowable head pressure and its optimum head pressure. Frequently, the optimum head pressure is at a figure which is 25 percent below the maximum rating. For a typical two ton air conditioner, the maximum head pressure is typically identified as 400 pounds, while the optimum rating is typically identified as 300 pounds. When the compressor is operating at 400 pounds, its cooling capacity can be reduced by as much as 50% over its rated cooling capacity at 300 pounds. More specifically, this means that the efficiency of a two ton air conditioner rated at 95.degree. F with an optimum head pressure of 300 pounds when operated at a temperature above its rated temperature, i.e., 110.degree. F, with a head pressure of 400 to 425 pounds, is frequently reduced by 50% and hence operates as a one ton unit. Obviously, a one ton unit will have to work at least twice as long to provide the required cooling of a two ton unit. This added time causes an increase in the cycle time of the air conditioning unit.
The cycle time of an air conditioning unit is divided between its "on time" and its "off time." A two ton unit operating at its rated temperature has an "on time" during which it is used to cool the air inside a house to a desired level selected by the home owner and an "off time" during which the air conditioner is off and not operating. The "on time" of an air conditioning unit is principally a function of the air temperature identified by the thermostat, the insulation of the house itself which determines how fast the cool air leaks out of the house to be replaced by the ambient air temperature, and the efficiency of the compressor. The efficiency of the compressor is best maximized by its operation at an ambient air temperature at or below its rated temperature. The establishment of the improved ambient temperature has the following main advantages: first the "on time" is reduced because the coolant is cooled to its "coolant differential temperature" quicker and with less power; second, the "off time" is extended because of the reduction of "on time" thus reducing the wear and tear on the machinery.
Aluminum is a common material used throughout the condenser unit. The coils are often times made of aluminum as well as other parts of the air conditioning system. In prior art, air treatment systems using water, a problem which occurs in these systems is the injection of water droplets into the air stream. The water droplets are carried to the condenser unit where a particular problem occurs. when the water droplets deposit upon the cooling coils, the water acts as an insulator between the consenser surface covered by the water and the air passing over the condenser coil. The area covered by the water does not participate in the cooling operation and the cooling efficiency of the condenser is further reduced.
Certain of the prior art air conditioning systems, which used a precooler for the condenser unit, often times employed an evaporative member which actually was an obstruction to the flow of air through the evaporative member prior to its passing over the condenser coils. Such an obstruction required additional energy to pull the required amount of air over the condenser coils. Typically, a fan is used to cause air to flow through a prior art evaporative member and then over the condenser coils. Hence, additional fan power is required because of the obstructionistic effect of the prior art evaporative member.
In an aggravated situation, i.e., wherein the obstructionistic effect was pronounced, the air passed over the condenser coils in a shadow-like effect of the fan. The shadow was approximately equal to the area of revolution of the fan blades. Typically, the area of the condenser coil is larger than the area of revolution of the fan. In such a situation, the air would only pass over the condenser coils in a shadow image of the fan. This resulted in a portion of the condenser coils being outside of the shadow effect. This area outside of the shadow effect did not contribute to the cooling efforts of the condenser. This also reduced the efficiency of the condenser.